[Greenbuilding] insulating on sheathed roof

[Bob]

I concur with Laren on almost all points.   However, I recommend a 
closer spacing if you are trying to dense pack through 1 or 1.5" holes.  
Our testing on demo walls, with less obstruction than a wall with 
existing batts, showed that, using the sort of blower that is typically 
available for rent, cellulose would pack reliably about 1.5' from the 
hole/nozzle.  A truck mount blower is probably capable of more pressure 
and a wider pack radius, but I wouldn't count on it unless the finished 
job was to be verified by infrared scanning.

I like the idea of using multiple access holes where there is existing 
batt.   I've tubed similar walls as a favor and experiment and it is a 
slow, uncertain process that I couldn't recommend. However, it is still 
my favorite technique for empty cavities.

I'm leery of assuming that the loaner blowing machines, based on what 
has been available locally.  In my experience they are fine for open 
area blowing but lack the air pressure for adequate dense packing but my 
experience may be dated .  I can rent a Force One locally for jobs like 
that.  It's small enough for the average homeowner / DIYer to handle and 
powerful enough to use for dense packing.  Judging from the advertising 
specs, there are other small machines with those capabilities but I 
haven't had an opportunity to try them.
Bob Klahn

Laren Corie wrote:
> From: "John E. Beeson" <jbeeson at quinnevans.com>
>   
-dense-pack cellulose.-
>  --From the inside, it can go through
> 1" (or 1-1/8") holes about every five feet, or a long
> hose can be fed through a single hole at the top of
> each joist space, then gradually pulled up.---
> --- with most purchases a 24hr rental of a blower is free.
> Prep before getting the blower, and it should
> only take a few hours to fill the whole roof.
>